Fig. 2
From: IL-18 associated with lung lymphoid aggregates drives IFNγ production in severe COPD
IL-18 is expressed by lung epithelial cells and is associated with an apical lining in GOLD 4 COPD patients. a Bright field micrographs exemplifying epithelial IL-18 immunostaining in a control lung sections (upper panel) and in GOLD 4 patients (lower panel). Immunoreactivity is visualized by brown DAB chromogen. Arrow head indicates apical surface of small airway. Scale bar = 70 μm. b Quantification of IL-18 apical staining across patient groups. Each data point represents a mean value for multiple airways analysed for each patient; Number of patients in each group: Never smokers n = 8, Smokers n = 7, COPD GOLD Stage 1 n = 6, COPD GOLD Stage 2–3 n = 14 and COPD GOLD Stage 4 n = 10. Numbers of airways quantified for each patient varied but were >3 per patient. Data is summarised with a boxplot, showing the minimum, maximum, first quartile, third quartile and median. Outliers are identified as data points beyond the first and third quartile by at least the 1.5xInterquartile range. A generalised least square model with heterogeneous variance was fitted to explore the effect of the smoking/disease status on the IL-18 readings